Lately, economists have discovered an unsettling phenomenon: While top companies are getting more productive, gains are stalling for everyone else. And the gap between the two is widening, with globalization and new technology delivering outsize rewards to the titans of the global economy.

“Whatever good stuff is happening at the high end is not diffusing down to the tail,” says Andrew Haldane, chief economist at the Bank of England.

Your suspicions are correct: The biggest companies in every field are pulling away from their peers faster than ever, sucking up the lion’s share of revenue, profits and productivity gains.

Economists have proposed many possible explanations: top managers flocking to top firms, automation creating an imbalance in productivity, merger-and-acquisition mania, lack of antitrust regulation and more.

But new data suggests that the secret of the success of the Amazons, Googles and Facebook s of the world—not to mention the Walmart s, CVSes and UPSes before them—is how much they invest in their own technology.